Charger design has been simplified through chips that embed charge intelligence. When first introduced in the 1980s, these chips were hot commodities and were made popular with the arrival of NiMH and Li-ion that need special charging algorithms. Charger chips have since matured and serve in more basic charging devices.
Although charger chips are easy to use, they have limitations. Most offer a fixed charge algorithm that does not permit fine-tuning for specialty uses. Features such as “boost,” which reactivates the protection circuit when a Li‑ion battery falls asleep, do not exist, nor can a charger chip accommodate different chemistries selectable by a code, or do ultra-fast charging with safeguards that include scaling the charge current to battery condition and temperature. Temperature control is mostly through an on/off switch.
Microcontrollers offer an alternative to charger chips. Although the design cost is higher because of programming, manufacturing costs are compatible to charger chips. We must keep in mind that the charge chip or microcontroller form only a small part of the charger circuit, and the bulk of the cost lies in the peripheral components, which include solid-state switches and the power supply. The cost of these parts is in direct relationship to current handling.